RESUMO
Treatment of bacterial infections is becoming a serious clinical challenge due to the global dissemination of multidrug antibiotic resistance, necessitating the search for alternative treatments to disarm the virulence mechanisms underlying these infections. Uropathogenic Escherichia coli (UPEC) employs multiple chaperone-usher pathway pili tipped with adhesins with diverse receptor specificities to colonize various host tissues and habitats. For example, UPEC F9 pili specifically bind galactose or N-acetylgalactosamine epitopes on the kidney and inflamed bladder. Using X-ray structure-guided methods, virtual screening, and multiplex ELISA arrays, we rationally designed aryl galactosides and N-acetylgalactosaminosides that inhibit the F9 pilus adhesin FmlH. The lead compound, 29ß-NAc, is a biphenyl N-acetyl-ß-galactosaminoside with a Ki of â¼90 nM, representing a major advancement in potency relative to the characteristically weak nature of most carbohydrate-lectin interactions. 29ß-NAc binds tightly to FmlH by engaging the residues Y46 through edge-to-face π-stacking with its A-phenyl ring, R142 in a salt-bridge interaction with its carboxylate group, and K132 through water-mediated hydrogen bonding with its N-acetyl group. Administration of 29ß-NAc in a mouse urinary tract infection (UTI) model significantly reduced bladder and kidney bacterial burdens, and coadministration of 29ß-NAc and mannoside 4Z269, which targets the type 1 pilus adhesin FimH, resulted in greater elimination of bacteria from the urinary tract than either compound alone. Moreover, FmlH specifically binds healthy human kidney tissue in a 29ß-NAc-inhibitable manner, suggesting a key role for F9 pili in human kidney colonization. Thus, these glycoside antagonists of FmlH represent a rational antivirulence strategy for UPEC-mediated UTI treatment.
Assuntos
Adesinas de Escherichia coli/química , Antibacterianos/química , Antibacterianos/farmacologia , Aderência Bacteriana/efeitos dos fármacos , Infecções Urinárias/microbiologia , Adesinas de Escherichia coli/metabolismo , Animais , Cristalografia por Raios X , Avaliação Pré-Clínica de Medicamentos/métodos , Infecções por Escherichia coli/tratamento farmacológico , Infecções por Escherichia coli/microbiologia , Feminino , Galactosídeos/síntese química , Galactosídeos/química , Humanos , Rim/efeitos dos fármacos , Rim/metabolismo , Rim/microbiologia , Ligantes , Camundongos Endogâmicos C3H , Simulação de Acoplamento Molecular , Mimetismo Molecular , Infecções Urinárias/tratamento farmacológico , Escherichia coli Uropatogênica/efeitos dos fármacos , Escherichia coli Uropatogênica/patogenicidadeRESUMO
Allosteric modulators of the serotonin (5-HT) 5-HT(2C) receptor (5-HT(2C)R) present a unique drug design strategy to augment the response to endogenous 5-HT in a site- and event-specific manner with great potential as novel central nervous system probes and therapeutics. To date, PNU-69176E is the only reported selective positive allosteric modulator for the 5-HT(2C)R. For the first time, an optimized synthetic route to readily access PNU-69176E (1) and its diastereomer 2 has been established in moderate to good overall yields over 10 steps starting from commercially available picolinic acid. This synthetic approach not only enables a feasible preparation of a sufficient amount of 1 for use as a reference compound for secondary pharmacological studies, but also provides an efficient synthesis of key intermediates to develop novel and simplified 5-HT(2C)R allosteric modulators. Compound 1 and its diastereomer 2 were functionally characterized in Chinese hamster ovary (CHO) cells stably transfected with the 5-HT(2C)R using an intracellular calcium (Ca(i) (2+)) release assay. Compound 1 demonstrated efficacy and potency as an allosteric modulator for the 5-HT(2C)R with no intrinsic agonist activity. Compound 1 did not alter 5-HT-evoked Ca(i) (2+) in CHO cells stably transfected with the highly homologous 5-HT(2A)R. In contrast, the diastereomer 2 did not alter 5-HT-evoked Ca(i) (2+) release in 5-HT(2A)R-CHO or 5-HT(2C)R-CHO cells or exhibit intrinsic agonist activity.
Assuntos
Galactosídeos/síntese química , Galactosídeos/farmacologia , Piperidinas/síntese química , Piperidinas/farmacologia , Receptor 5-HT2C de Serotonina/metabolismo , Regulação Alostérica/efeitos dos fármacos , Regulação Alostérica/fisiologia , Animais , Células CHO , Cálcio/metabolismo , Cricetinae , Cricetulus , Avaliação Pré-Clínica de Medicamentos/métodos , Galactosídeos/química , Humanos , Piperidinas/química , Receptor 5-HT2C de Serotonina/fisiologia , EstereoisomerismoRESUMO
Ergosterol 3-O-ß-D-glucopyranoside (1a) and ergosterol 3-O-ß-D-galactopyranoside (1b) were highly efficiently synthesized and evaluated for their inhibitory activities against two tumor cell lines. The structures of these compounds were extensively confirmed by (1)H, (13)C NMR, IR, and HRMS. Compounds 1a and 1b exhibited interesting cytotoxic profiles. The antitumor activity of compound 1a was higher than that of 1b.
Assuntos
Antineoplásicos Fitogênicos/síntese química , Antineoplásicos Fitogênicos/farmacologia , Cordyceps/química , Ergosterol/análogos & derivados , Ergosterol/síntese química , Ergosterol/farmacologia , Galactosídeos/síntese química , Galactosídeos/farmacologia , Glucosídeos/síntese química , Glucosídeos/farmacologia , Saponinas/síntese química , Saponinas/farmacologia , Antineoplásicos Fitogênicos/química , Ensaios de Seleção de Medicamentos Antitumorais , Ergosterol/química , Galactosídeos/química , Glucosídeos/química , Humanos , Medicina Tradicional Chinesa , Estrutura Molecular , Ressonância Magnética Nuclear Biomolecular , Saponinas/químicaRESUMO
para-Nitrophenol-tagged sialyl galactosides containing sialic acid derivatives in which the C5 hydroxyl group of sialic acids was systematically substituted with a hydrogen, a fluorine, a methoxyl or an azido group were successfully synthesized using an efficient chemoenzymatic approach. These compounds were used as valuable probes in high-throughput screening assays to study the importance of the C5 hydroxyl group of sialic acid in the recognition and the cleavage of sialoside substrates by bacterial sialidases.
Assuntos
Galactosídeos/síntese química , Neuraminidase/química , Ácidos Siálicos/química , Antibacterianos/síntese química , Proteínas de Bactérias/antagonistas & inibidores , Avaliação Pré-Clínica de Medicamentos , Neuraminidase/antagonistas & inibidores , Neuraminidase/metabolismo , Relação Estrutura-Atividade , Especificidade por SubstratoRESUMO
Gene therapy holds great promise for the treatment of diverse diseases, but widespread implementation is hindered by difficulties in assessing the success of transfection. The development of noninvasive reporter techniques based on appropriate molecules and imaging modalities may help to assay gene expression. Fluorophenyl-beta-d-galactopyranosides provide a novel class of NMR active molecules, which are highly responsive to the action of beta-galactosidase (beta-gal), the product of the lacZ gene. The reporter molecules are stable in solution and with respect to wild-type cells, but the enzyme causes liberation of the aglycon, a fluorophenol, accompanied by distinct color formation and a (19)F NMR chemical shift of 5-10 ppm, depending on pH. Synthetic strategy, experimental methods, and molecular and (19)F NMR characteristics are reported for a series of molecules in solution, blood, and tumor cells. This class of molecules presents a new strategy for assaying gene expression with a highly versatile molecular structural platform.